There are a number of reasons why a disaster shelter might be built. Along the east coast of the United States and parts of the Asian coastline, they protect people from hurricanes, flooding and typhoons.

The Null Stern Hotel: a shelter conversion

In earthquake-prone regions, they shelter people from falling buildings and provide an escape route from surface rubble when all is clear. And typically across the Great Plains of the US, simple but sturdy shelters offer a safe subterranean retreat from tornadoes wreaking havoc on the surface.

Nuclear bunkers are the most robust of these shelters. They’re designed to provide comprehensive safety from anything nature or man can throw at them, plus life support for many months – and even years for the most sophisticated examples.

Smaller varieties tend to come pre-assembled, but larger and bespoke shelters are usually installed on site. The modern shape is a corrugated curve, made of fibreglass and composite, fire retardant and even bulletproof (for the entrance) materials. They’re designed to avoid tensile loads, while seismic joints can withstand the kind of forces an 8.5-magnitude earthquake might yield.

Modern nuclear bunkers are sealed to prevent contamination from nuclear fallout and also to keep deadly radon gas and airborne toxins out, including weaponised viruses and bacteria. In addition, an ‘overpressure choking’ system with no moving parts prevents a nearby blast from causing excessive pressure inside the shelter.

New nuclear bunkers are still a profitable business today despite the decades that have passed since the Cold War ended. While they are a fascinating feature for any household to have, we can only hope that no one ever has to use them for their intended purpose.